In Greek mythology, Hyperion (Greek: Ὑπερίων, “The High-One”) was one of the twelve Titan children of Gaia (Earth) and Uranus (Sky or Heaven) who, led by Cronus, overthrew Uranus and were themselves later overthrown by the Olympians. With his sister, the Titaness Theia, Hyperion fathered Helios (Sun), Selene (Moon) and Eos (Dawn).
Hyperion’s son Helios was referred to in early mythological writings as Helios Hyperion (Ἥλιος Ὑπερίων, “Sun High-one”). In Homer’s Odyssey, Hesiod’s Theogony and the Homeric Hymn to Demeter, the Sun is once in each work called Hyperionides (Ὑπεριωνίδης, “son of Hyperion”), and Hesiod certainly imagines Hyperion as a separate being in other writings. In later Greek literature, Hyperion is always distinguished from Helios; the former was ascribed the characteristics of the “God of Watchfulness, Wisdom and Light”, while the latter became the physical incarnation of the Sun. Hyperion is an obscure figure in Greek culture and mythology, mainly appearing in lists of the twelve Titans:
Of Hyperion we are told that he was the first to understand, by diligent attention and observation, the movement of both the sun and the moon and the other stars, and the seasons as well, in that they are caused by these bodies, and to make these facts known to others; and that for this reason he was called the father of these bodies, since he had begotten, so to speak, the speculation about them and their nature.
—Diodorus Siculus (5.67.1)
There is little to no reference to Hyperion during the Titanomachy, the epic in which the Olympians battle the ruling Titans, or the Gigantomachy, in which Gaia attempts to avenge the Titans by enlisting the aid of the giants (Γίγαντες) that were imprisoned in Tartarus to facilitate the overthrow of the Olympians. Source Wikipedia.